The key to preventing mildew is to avoid storing soiled articles in damp conditions.
Soiled clothes should be kept dry and should be cleaned as soon as possible. Dirty clothes that are damp should not be stored in a pile or in a clothes hamper.
Store clothes for long periods only when they are clean, dry, and unstarched.
Storage areas should be clean and dry. Fabrics should not be stored in damp closets, bathrooms, or basements. Storage containers and/or drawers should be clean.
Prevent high humidity in the storage areas with good ventilation, air conditioning, and/or a dehumidifier. A burning light bulb in a storage closet can help keep air dry.
During periods of high humidity, exposing garments to air and sun can help prevent mildew.
Correct any causes of excessive dampness in the house. Any problems with drainage, waterproofing or caulking should be corrected immediately.